1. Field of the Invention
The present invention relates to speech synthesis.
2. Description of the Related Art
Conventional text speech synthesis apparatuses often carry out syntactic analysis in which the modification relations of a text are analyzed in order to obtain clue information for prosody control from the text. Syntactic analysis for completely analyzing the modification relations of one sentence generally requires a large number of calculations. Thus, to obtain modification information on a text with a small number of calculations, for example, JP-A 10-83192 (KOKAI) (Document 1) discloses a method of carrying out syntactic analysis on the basis of the pre-specified strength of the dependence between prosodic word types to determine the strengths of prosodic phase boundaries. Speech synthesis apparatus performs prosodic control using prosodic information generation means characterized by generating prosodic information for text information taking into account the strengths of prosodic phase boundaries obtained from the text.
Document 1 requires advanced expertise to define the strength of the dependence between prosodic word types. Document 1 thus disadvantageously requires much time and effort to newly develop TTS systems or to maintain existing TTS systems. Further, according to Document 1, syntactic analysis requiring a large number of calculations is unavoidable. Consequently, this technique is disadvantageously difficult to apply to a built-in system with a relatively low computation capacity.